In the definition of economics, exchange rate is the exchange rate between two countries' currencies. Usually, the currency of one country is used as a benchmark to exchange currencies of other countries with a value of several yuan. In the use of English, it is sometimes abbreviated as FX, which is the abbreviation of foreign currency and foreign exchange. Generally speaking, it is the ratio of one country's monetary unit to another, and it can also be said that it is the price of another country's currency expressed in one country's currency. The exchange rate is characterized by mostly floating exchange rates.

Exchange rate is also called exchange rate, foreign exchange quotation or foreign exchange market, that is, the buying and selling price of foreign exchange. Different monetary systems have different formulation methods. Under the gold standard, due to the different gold contents of currencies in different countries, the comparison of the gold contents of the two currencies (also called coinage parity) is the basis of foreign exchange rate. Under the dishonoured credit currency system, exchange rate changes are restricted by the relationship between foreign exchange supply and demand. When a currency is in short supply, its exchange rate will rise, and when a currency is in short supply, its exchange rate will fall.

Gross domestic product is the abbreviation of gross domestic product calculated at market price. It is the final result of the production activities of all permanent units in a country (region) in a certain period of time. There are three forms of GDP, namely, value form, income form and product form. From the perspective of value form, it is the difference between the value of all goods and services produced by all permanent units and the value of all non-fixed assets goods and services invested in the same period, that is, the sum of the added value of all permanent units; From the perspective of income form, it is the sum of the initial distribution income created by all permanent units and distributed to permanent units and non-permanent units in a certain period of time; From the product form, it is the final use of goods and services minus imported goods and services. In actual accounting, three forms of GDP are expressed by three calculation methods, namely, production method, income method and expenditure method. The three methods reflect GDP and its composition from different aspects.

Futures is a contract that must be fulfilled in the future, not a specific commodity. The content of the contract is unified and standardized, but the price of the contract will fluctuate in different sizes due to changes in various market factors. The "goods" corresponding to this contract are called the subject matter. Generally speaking, the "goods" to be speculated in futures are the subject matter, which is embodied by contract symbols. For example, CU0602 is a symbol of futures contract, which means a contract delivered in February 2006, and the subject matter is electrolytic copper.